what on earth do you mean by "professional"? and how can your software be "expensive" if it is also FOSS?
or is this satire?
or is this satire?
Notice that I said that I will be expensive, not the FOSS. I meant that my services will be expensive.
So yes, I will. Thank you.
FOSS means free, depending on what you want from the software - if you want more than the FOSS offering does, you may have to pay for improvements, or you may not.
I can't help you with your disbelief, but it is true that nothing in the FOSS philosophy prevents companies from charging for their work.